<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <script>
        var num = prompt("请您输入一个数字(0~6).");
        num = +num;
        if(num){
            if(num == 0){
            alert("今天星期日!!!");
        }else if(num == 1){
            alert("今天星期一!!!");
        }
        else if(num == 2){
            alert("今天星期二!!!");
        }
        else if(num == 3){
            alert("今天星期三!!!");
        }
        else if(num == 4){
            alert("今天星期四!!!");
        }
        else if(num == 5){
            alert("今天星期五!!!");
        }
        else if(num == 6){
            alert("今天星期六!!!");
        }
        }else{
            alert("请输入正确的数字");
            location.reload();
        }
        
    </script>
</body>

</html>